Apparatus for forming a stack

ABSTRACT

An apparatus for applying an adhesive-coated cover sheet or lamina to a substrate, such as a particulate or fibrous core, has a pair of substantially parallel surfaces which lie next to each other and form beds for the sheet and the substrate, respectively. Pivoted between these surfaces is a fork which can swing through an arc of close to 180* and has tines for lifting the adhesive-free underside of the sheet so that it can swing this sheet to a position above the substrate. A depositing arrangement is pivotal about an axis close to the fork pivot axis through the balance of the 180* arc so that it receives the sheet from the fork and moves it to immediately adjacent the substrate; the depositing device is displaced transversely to the pivot axis to the side, gently placing the sheet on the substrate. The surface of this placing arrangement is formed by a plurality of parallel cables which are spanned over a transversely displaceable guide.

United States Patent [1 1 3,704,883 Don [451 Dec. 5, 1972 [5 APPARATUS FOR FORMING A STACK Primary Examiner-Even C. Blunk [72] Inventor: Gunter Don, Hiddesen Gerrnany Filed:

Assignee: G. Siempelkamp 8: C0,, Krefeld,

Germany Feb. 17, 1971 Appl. No.: 116,203

US. Cl. ..271/72, 156/556, 214/6 DK,

References Cited UNITED STATES PATENTS Scott ..27ll70 Cornwall ..271/73 Dryon ..2l4/6 DK Califano et al ..l56/538 UX Hutz ..l98/l02 Assistant Examiner-Bruce H. Stoner, Jr. Attorney-Karl F. Ross ABSTRACT An apparatus for applying an adhesive-coated cover sheet or lamina to a substrate, such as a particulate or fibrous core, has a pair of substantially parallel surfaces which lie next to each other and form beds for the sheet and the substrate, respectively. Pivoted between these surfaces is a fork which can swing through an arc of close to 180 and has tines for lifting the adhesive-free underside of the sheet so that it can swing this sheet to a position above the substrate. A depositing arrangement is pivotal about an axis close to the fork pivot axis through the balance of the 180 are so that it receives the sheet from the fork and moves it to immediately adjacent the substrate; the depositing device is displaced transversely to the pivot axis to the side, gently placing the sheet on the substrate. The surface of this placing arrangement is formed by a plurality of parallel cables which are spanned over a transversely displaceable guide.

10 Claims, 4 Drawing Figures PATENTED 5l972 3.704.883

SHEET 1 OF 3 INVENTOR: GUNTER DON BY Karl Ross ATTORNEY PATENTED EB we 3.704.883

' SHEET 3 [IF 3 F I G 4 I NVENTOR:

GUNTER 00w AT TORINEY 1 APPARATUS FOR FORMING A STACK FIELD or THE INVENTION The present invention relates to an apparatus for applying a sheet to a substrate and, more particularly, to an apparatus for applying an adhesive-coated lamina to a noncoherent or only slightly coherent core.

BACKGROUND OF THE INVENTION In the manufacture of many types of surface-finished pressed laminates and various types of paneling, a thin decorating, sealing or finishing lamina or sheet of wood, synthetic resin, paper or metal foil, is bonded to a relatively thick core. The lamina can be a syntheticresin foil intended to impart heat-resistance and waterproof qualities to the core, or it can bea very thin veneer of high-grade hardwood adapted to mask a core of low-grade wood chips or fibers to give it the appearance of fine paneling. The core is of only limited coherency or of low-grade material; for example, it may consist of incompletely bonded or unbonded fibers, particles or chips of wood or cellulose. When a noncoherent core is described herein, the aforementioned structure is intended.

It has been the practice to fully press the core and then coat its upper face with adhesive so that the lamina need merely be laid on it. This can be carried out by a simple reciprocating roller arrangement or by means of vacuum lifters.

In more recent times it has been found, however, that it is possible to form a core of very regular cross-sectional dimensions, so that elimination of the prepressing step seemed possible. This requires application of the glue or adhesive to the underside of the lamina, so that significant problems have arisen. For example, many kinds of laminae lose much of their strength when so coated, thereby making it difficult to simply spray the underside of a sheet held by a vacuum lifter. In addition, suction handling of laminae having one gluey side is difficult and the core cannot simply be sprayed, since a heavy local application of adhesive is required just at the core-lamina interface.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide an improved apparatus for applying a sheet to a substrate.

Another object is to provide an apparatus that can apply a sheet having one adhesive-coated face to a noncoherent or only slightly coherent plate-like core and which does not exhibit the above-given disadvantages.

Still another object of the present invention is to provide an improved method of forming a laminate or stack in a convenient manner using thin glue-coated cover sheets.

SUMMARY OF THE INVENTION The above objects are attained, according to the present invention, by an apparatus having means defining a first surface adjacent the substrate for supporting the sheet and means defining a second surface immediately above the substrate. A fork has tines engageable with the sheet and is pivotal about a horizontal axis disposed between the first surface and the substrate; means is provided for pivoting the fork about its axis between a first position with the tines below the first surface and a second position adjacent and above the second surface. Means (depositing means) is also provided for displacing the second surface out from between the substrate and the sheet transversely to the fork pivot axis. In this manner the fork picks the sheet up off the first surface, turns it over, and deposits it on the second surface which in turn retracts laterally depositing the sheet on the substrate.

Such an apparatus allows the application of a sheet having its upper side coated with glue to a nearby substrate, the gluey side of the sheet being brought into engagement with the core. The pivot speed of the fork should be considerable whereby the sheet is held against the fork by its air-resistance force as much as possible. To this end, according to another feature of the present invention, the first surface and the substrate.

are disposed in respective parallel planes, possibly a common plane, while the fork pivots through a major are a, in excess of ninety degrees and preferably close to and means is provided to pivot the second surface about an axis parallel to or coinciding with the fork pivot axis through a minor are [3 where B z 180 a. In this case the pivot speed of the second surface is much less than that of the fork, since a careful placement is necessary and wind resistance is no longer used.

This second surface, in accordance with another feature of the invention, is formed by a plurality of parallel cables spanned with a relatively constant tension over a guide displaceable transverse to the axes, with the upper cable stretch being anchored at one end e.g. to the frame defining the pivotal second surface) and the lower cable stretch being retracted as the guide is moved back DESCRIPTION OF THE DRAWING The above and other objects, features and advantages will become apparent from the following description, reference being made to the accompanying drawing, in which:

FIG. 1 is a cross-section through the apparatus according to the present invention;

FIG. 2 is a top view of the apparatus; and

FIGS. 3 and 4 are diagrammatic views similar to FIG. 1 and showing the apparatus in two different work positrons.

SPECIFIC DESCRIPTION As seen in FIGS. 1 and 2 the apparatus serves in the application of a foil 1 to a substrate 2, 3. The foil 1 can be an synthetic-resin sheet, such as of the melamineformaldehyde type, to make hard heat-resistant panels. The substrate 2, 3 consists of a hard sheet 3 on which has been deposited a core 2 of comminuted, fibrous or chipped material. This core 2 is not coherent, but merely has been carefully deposited on the sheet 3 by methods such as the one described in the commonly assigned patent application Ser. No. 737,465 filed 17 June 1968 by Gerhard Hiitz and entitled METHOD OF AND PLANT FOR THE PRODUCTION OF IN- TEGRATED LAMINATES, wherein a plurality of hoppers filled with differently graded material continuously deposit on a transport band a very even carpet that is subsequently subdivided into individual mats. Each of the sheets 1 is, further, coated on its upper surface with an adhesive by gluing means 27 located upstream in the direction of travel of the sheets 1 as indicated by arrow A.

The sheets 1 rest on a bed formed by a plurality of parallel rollers 6 extending perpendicular to the transport direction A and defining a horizontal planar surface onto which the sheet 1 is rolled. The substrate 2, 3 is received on an endless belt 4 spanned over a pair of rollers 4', one of which is intermittently driven by a motor 28 to advance the upper surface of the belt in the transport direction A.

it is, of course, necessary to place the sheets 1, glue side down, on the substrate 2, 3. This requires turning over the sheet 1. A transfer fork 7 cooperating with a placing apparatus 9 carries out this function. It must be recognized that the sheet 1 has to be pivoted through 180, but that it cannot simply be dropped onto the noncoherent mat 2 since this would blow away some of the material forming this mat and would result in an inaccurate placement. Slowly flipping the sheet 1 is impossible without gripping it on both faces. The form 7 here operates rapidly, as will be described below, to flip or turn over the sheet 1 so that wind resistance holds it against the fork, while the arrangement 9 serves to place the turned-over sheet 1 carefully on the substrate 2, 3.

The form 7 comprises a pair of parallel tines 8 which are engageable between the rollers 6 and below the surface 5 formed thereby. These tines 8 are all connected at one end to a pivot shaft 12 which defines a straight pivot axis in line with the transport direction A and parallel to and slightly below the planar surface 5. The other ends of the tines 8 are optionally interconnected by a rod 12, and a motor 29 is intermittently actuated to sweep this fork 7 back and forth through an arc of a 165 to 170. The tines 8 are very light and do not come into contact with the gluey face of the sheet 1.

The placing device (depositing means) 9 includes a plurality of cables 17 which define a planar surface 24 adapted to receive the sheet 1 from the fork 7, gluey face down, and thereafter displace itself out of the transverse to the axis 12 way under the sheet 1 to lay this sheet 1 gently on the substrate 2, 3. These cables 17 are all anchored securely on the machine frame at 18 (or to a frame formed by arms and at their other ends they are wound up on a plurality of coaxial windlass pulleys 19 (one shown) mounted on a common shaft connected to a torque motor 14 which is constantly energized to rotate the drums 19 in the direction shown by arrow 31 to hold these cables 17 very taut. The cables pass over a roller 16 adjacent to which is provided an elongated wedge-shaped nosepiece 32 similar to that provided in the commonly assigned US. Pat. No. 3,482,675 issued 9 Dec. 1969. Either the nosepiece 32 or the roller 16 can be dispensed with. Thence they are spanned over a pair of rollers 33 and 34. This provides a surface of large effective surface area but very small actual surface area so that the glue on the sheet 1 is not stripped off, not can a cushion of air form between the sheet 1 and the surface 24. The cables 17 are spaced, to this end, as far apart as possible while sufficiently supporting the sheets 1. Since the roller 16 and nosepiece 32 are not of great thickness and since the roller 33, which like the roller 34 is a long freely rotatable cylinder provided with circumferential grooves, is only a few centimeters below the attachment points 18, the effective height of the arrangement 9 being small.

The roller 16 is joumaled in a pair of rigid arms 15 which also carry the nosepiece 32. Each arm 15 is displaceable transversely to the axis of the traverse 12. To this end, the end of each arm 15 remote from the roller 16 is received on a carriage 35 which rides by means of rollers 35 on a normally horizontal beam 21. Each beam 21 carries at one end a motor 13 whose shaft is provided with a sprocket 37 over which is engaged a chain 20 also passing around a sprocket 38 at the other end of the beam 21. The chain 20 is attached to the arm 15 at 39 so that rotation of the motor 13 in one sense moves the carriage in one direction on the beam 21 and in the other sense moves it in the opposite direction. This allows the arrangement 9 to be pulled out from between a sheet 1 and substrate 2, with the cables 17 being wound up on the pulleys 19 advantageously placed far enough from the arrangement 9 so that no part of the cables 17 which engaged the gluey face of the sheet 1 reaches the pulleys 19.

The beams 21 are pivoted under the axis 12 about an axis 22, and are connected at 40 at their opposite end to respective hydraulic cylinder arrangements 32 to pivot the arrangement 9 through an arc 10' of B 20 to 25.

The apparatus operates as follows, with particularv reference to FIGS. 3 and 4.

A substrate 2, 3 and a sheet 1 are fed into their respective surfaces 4 and 5, with the fork 7 down in the position shown in FIG. 2 and in the region 1 of FIG. 3. The cylinders 23 are contracted to lift the end of the surface 9 and the motor 13 is driven to fully extend this surface. Then the motor 29 is actuated to swing the fork 7 through the are 10 and deposit the sheet 1, glue side down, on the cables 17 (position 11 in FIG. 3). The motor 29 is subsequently reversed and the cylinders 23 are extended to move the surface 9 into a plane parallel and between the two parallel but vertically offset planes 4 and 5. Thereupon the motor 13 is actuated to retract through a distance 11 the roller 16 to the right, as shown in FIG. 4, thereby depositing the sheet 1 gently on the mat 2. The various movements can be controlled by limit switches and photoelectric cells.

Thereafter the sandwich can bepressed by, for example, a platen press as described in the aboveidentified patent.

The speed at which the arrangement 9 is pivoted is much less than that at which the fork 7 is pivoted, this being possible since, from the position 11, the arrangement 9 need merely pivot through 20 to 25, retract, pivot back, and extend again, while at the same time the fork 7 must swing through to a sheet must be rolled over this fork, and it must swing back. Thus a gentle deposition is possible along with a very high overall production speed. The sheet 1 is only moved slowly immediately adjacent the substrate 2, 3 since only in this region could overly rapid handling lead to difficulties. Conventional limit switches, lightbeam/photocell arrangements and the like may be used to control fork swing and cable retraction.

The only part of this apparatus which comes into contact with the glue on the upper side of the sheet 1 is the cables 17, which are easily cleaned.

I claim:

1. An apparatus for applying a sheet to a substrate, said apparatus comprising:

means defining a first surface adjacent the substrate for supporting the sheet;

a fork having tines engageable with said sheet and being pivotal about an axis parallel to said first surface and disposed between said first surface and said substrate;

means forming a second surface immediately above said substrate;

means for pivoting said fork about said axis between a first position with said tines below said first surface and a second position adjacent and above said second surface and thereby picking said sheet up off said first surface, turning it over, and depositing it on said second surface;

means for displacing said second surface out from between said substrate and said sheet transversely to said axis to lay said sheet on said substrante; and means for pivoting said second surface about an axis parallel to said substrate.

2. The apparatus defined in claim 1 wherein said first surface is parallel to said substrate, said means for displacing said second surface including a guide displaceable transversely to said axis.

3. The apparatus defined in claim 1 wherein said means forming said second surface includes a plurality of nonrigid elongated elements passing over said guide, each of said elements having one end fixed relative to the substrate and another end displaceable away therefrom, said means forming said second surface also including means connected to said other ends of said elements for making same taut to pull same over said guide on retraction of said guide toward said axis.

4. The apparatus defined in claim 1 wherein said elements are flexible cables.

5. The apparatus defined in claim 1 wherein said substrate and said first surface are substantially parallel, said fork being pivotal through a major arc and said second surface being pivotal through a minor arc, said arcs together extending over substantially 180.

6. The apparatus defined in claim 1 wherein said major arc extends over between and 7. The apparatus defined in claim 1 wherein said means for pivoting said second surface includes at least one upright hydraulic cylinder.

8. The apparatus defined in claim 1 wherein said means defining said first surface includes a plurality of rollers, said tines being engageable between said rollers.

9. The apparatus defined in claim 1 further comprising transport means forming a surface receiving said substrate for conveying said substrate into and out of said apparatus.

10. A method of forming a laminate comprising the steps of:

advancing a sheet in a transport direction to a position alongside a substrate;

pivoting said sheet through an angle between 90 and about an axis substantially parallel to said transport direction and laying said sheet on a sur face above said substrate;

moving said surface downwardly toward said substrate; and

withdrawing said surface out from between said sheet and said substrate in a direction transverse to said axis to depgsit said she et on said substrate. 

1. An apparatus for applying a sheet to a substrate, said apparatus comprising: means defining a first surface adjacent the substrate for supporting the sheet; a fork having tines engageable with said sheet and being pivotal about an axis parallel to said first surface and disposed between said first surface and said substrate; means forming a second surface immediately above said substrate; means for pivoting said fork about said axis between a first position with said tines below said first surface and a second position adjacent and above said second surface and thereby picking said sheet up off said first surface, turning it over, and depositing it on said second surface; means for displacing said second surface out from between said substrate and said sheet transversely to said axis to lay said sheet on said substrante; and means for pivoting said second surface about an axis parallel to said substrate.
 2. The apparatus defined in claim 1 wherein said first surface is parallel to said substrate, said means for displacing said second surface including a guide displaceable transversely to said axis.
 3. The apparatus defined in claim 1 wherein said means forming said second surface includEs a plurality of nonrigid elongated elements passing over said guide, each of said elements having one end fixed relative to the substrate and another end displaceable away therefrom, said means forming said second surface also including means connected to said other ends of said elements for making same taut to pull same over said guide on retraction of said guide toward said axis.
 4. The apparatus defined in claim 1 wherein said elements are flexible cables.
 5. The apparatus defined in claim 1 wherein said substrate and said first surface are substantially parallel, said fork being pivotal through a major arc and said second surface being pivotal through a minor arc, said arcs together extending over substantially 180* .
 6. The apparatus defined in claim 1 wherein said major arc extends over between 165* and 170* .
 7. The apparatus defined in claim 1 wherein said means for pivoting said second surface includes at least one upright hydraulic cylinder.
 8. The apparatus defined in claim 1 wherein said means defining said first surface includes a plurality of rollers, said tines being engageable between said rollers.
 9. The apparatus defined in claim 1 further comprising transport means forming a surface receiving said substrate for conveying said substrate into and out of said apparatus.
 10. A method of forming a laminate comprising the steps of: advancing a sheet in a transport direction to a position alongside a substrate; pivoting said sheet through an angle between 90* and 180* about an axis substantially parallel to said transport direction and laying said sheet on a surface above said substrate; moving said surface downwardly toward said substrate; and withdrawing said surface out from between said sheet and said substrate in a direction transverse to said axis to deposit said sheet on said substrate. 